Luminescent Carbon Dots for Optical Imaging

Technical Summary:

This quantum dot technology can be comprised of a single material with uniform internal compositions, such as chalcogenides of metals like cadmium, lead or zinc. The photo- and electroluminescence properties of core-type quantum dots can be fine-tuned by simply changing crystallite size. The luminescent properties of quantum dots arise from the recombination of electron hole pairs through radiative pathways. However, excitation decay can also occur through non-radiative methods, reducing the fluorescence quantum yield. One of the methods used to improve efficiency and brightness of these semiconductor nanocrystals is growing shells of another, higher-band gap semiconducting material around them. These quantum dots with small regions of one material embedded in another with a wider band gap are known as core-shell quantum dots (CSQDs) or core-shell semiconducting nanocrystals (CSSNCs). Coating quantum dots with shells improves quantum yield by passivizing non-radiative recombination sites and also makes them more robust to processing conditions for various applications.